Coronary artery disease (CAD) is one of the leading causes of death. CAD may be characterized by acute events or gradual events. Acute events may include plaque rupture that may demand immediate care. Gradual events may include accumulation of plaque, which may lead to progressive anatomic narrowing resulting in ischemia. One of the most widely used non-invasive clinical metrics for diagnosing patients with symptoms of coronary artery disease is percent stenosis derived from coronary computed tomography angiography (cCTA). Estimation of percent stenosis may involve two steps: (1) the measurement of local diameter and (2) the measurement of a reference health diameter. To measure percent stenosis, cCTA may provide information on the extent of anatomical narrowing in different regions of the coronary artery tree. The extent of anatomical narrowing in regions of the coronary artery tree may be a clinical measure used to decide between performing invasive angiography and pressure measurements or deferment of invasive measurements. In some embodiments, the extent of anatomical narrowing may be estimated categorically (e.g. 0%, 1-30%, 31-49%, 50-69%, 70-100%) in a clinic, or sent to a core lab for analysis. Quantitative computed tomography (QCT) and quantitative coronary angiography (QCA) may include methods where percent stenosis may be estimated as a number between 0 and 100. QCA may involve an invasive procedure evaluated on angiograms, and QCT, evaluated on cCTA's, may be time consuming and generally performed in a core lab. Accordingly, a desire exists to provide a safer and less time-consuming method of determining the extent of anatomical narrowing in regions of a coronary artery tree.
Determining the extent of narrowing entails first discerning a reference vessel diameter, e.g., a healthy lumen diameter. However, the estimation of a reference healthy diameter may be challenging in non-focal disease regions, for instance in diffuse, ostial, and bifurcation lesions. A desire also exists to estimate healthy lumen diameter in non-focal lesions.
The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.